The data flow generation activates or deactivates the data flow on the graphical objects in windows, and generates in the DECL_PGM section 4GL instructions for declaring views and loadings.
These instructions are placed between marker 4GL instructions BEGIN_STD_DFL and END_STD_DFL.
Warning:
Before generating data flow, all instructions between these 4GL instructions will be deleted.
Moreover, if the section contains instructions but does not contain the INSERT_STD_DFL nor BEGIN_STD_DFL / END_STD_DFL instructions, no instruction will be generated.
Click here for details about the corresponding 4GL instructions.
The data flow generation is made as follows:
- The entities are processed in the same order as when they were assigned on the window.
- The data items concerning a single entity are gathered under a single view.
- The view is automatically defined if there is not one equivalent (same entity or access, same type of use and same number of key fields).
When it comes to windows using a list, the load corresponding to this list is defined, together with the view corresponding to the update in case some information can be modified in the list. - When it comes to creating a new view:
- The entity or access to be used is determined from the properties constituting the access (access path). If the entity key is convenient for the access path specified, then the entity is taken into account; otherwise the first access with a convenient access path will be taken into account.
- Concerning the key fields of the views or loadings, those taken into account are:
- the first Input/Output screen field (or Output if it is the update view of the list) whose origin is the logical property defined in the access of the entity;
- the first screen field whose original logical property is different from the entity processed, but has the same original conceptual property;
- the field of the entity constituting the access.